Headwork

[Fitzy]

Hi Guys I have discovered a small oil weep in the head gasket on the rear jug on my bike so I thought when I replace it I may as well do both, so I may as well change the cam and if I do that I may as well shave the heads this could go on forever anyway. After a lot of research everyone here says 585 cam is the go would it pay to use the 585 and still shave the heads or should I go 600 if I'm going to shave the heads ? or don't touch the heads at all just cam ? and if I shave the heads how far do you go. I don't want a drag bike just thought if I have to pull the top end down may as well give it a bit of a tickle extra HP cant hurt. I would still like to run premium pump fuel.
08 Mutt 117
super G carb
2 into 2 big radius exuast
Your thoughts
Cheers

 

[HMAN]

Well, simple rule of thumb. When you tinker with things, you may just end up with a tinker toy..... With the 585, I believe you don't need to touch the heads. If you go beyond that, head work becomes part of the process. jm .02

 

[Alexey]

What do you want to do a lot more complicated than it seems. Do not be mad at me, but in the sense of your question it is clear that you do not know in depth the subject.
If you want to increase the power you need to shorten the cylinders. You need to know:
- The height of the deck piston.
- compression ratio.
- The desired compression ratio.
- Displacement the combustion chamber.
- Know all the formulas.
- Understand how much you need to cut cylinders.
- Take into account the increasing load.
- Learn how to calculate the camshaft
- Understand that such time of opening (degree) and the valve overlap time.
- Understand how to make the right hon.
- Take into account new gaps in the cylinder.
- Take into account the high temperatures.
- Understand how the traction and power depending on the time and type of overlap camshaft.
I advise you to take the books, to take engineering engine and teach. And to understand. After that, your questions will vary and you will be able to start the modification. I am doing so. Learn, learn and learn.
Do not be mad at me. In correspondence is impossible to explain in such a complex issue. I do not want, what would you kill your engine.
Start with replacing gaskets. And figure it out, carefully in all matters.

 

[SKOGDOG]

Hello Fitzy--a couple of years ago Blavktopper and I tore into my 117 because of a failed exhaust valve guide.
I had S&S rebuild the heads and look at the jugs. They were out of specs, so they bored them, which required new pistons. They shaved the jugs...I cannot recall how much, but it was mild. I regret not sending them to John Sachs, a Forum member. His work is just as good.
We installed a 585 cam because the 600 or 625 would benefit from stronger springs to prevent floating and bigger valves to move more air/fuel mix at higher rpm. (I'm not real smart, but do understand that if you mostly ride at 2,000 to 4,000 rpm, the 585 is good, if you want more juice at 4,000 to 6,000, rpm, use the 600 or 625.)
I had installed a Thunderheart ignition some years ago. I think that (and the cam) may have been the best performance enhancements.
The modifications are mild, but do result in significantly stronger performance compared to stock, and I have been satisfied with the results.
If your engine has over 25,000 miles, it is a good idea to replace your roller tappets as well. You don't want one of them failing. You also might think about adjustable pushrods too.
The "balance" for all of this is just how powerful you want it to be, and how much money you are willing to put into the engine. Keep in mind--- the increased power means increased internal force, which means shorter overall engine life. So if you build it big and ride hard for a lot of miles, keep good notes, because you'll be doing it all again at some point hahaha.

 

[Lorenzo]

On my 07 K9 i did 585 cams and had the heads shaved .020. It's a beast!

 

[Fitzy]

Thanks for response guys, I will go with a 585 cam and new roller tappets and might leave the heads alone. Rick i thought i already had adjustable pushrods .

 

[pauly]

Yes you do.

Paul

 

[spadesluck]

If you do indeed have the heads done John Sachs is a good guy to deal with. He did my heads and carb.

 

[BWG56]

Thanks for response guys, I will go with a 585 cam and new roller tappets and might leave the heads alone. Rick i thought i already had adjustable pushrods .

Good choice